Use of a wide variety of solvents is required for general-purpose liquid analyzers represented by flow injection analyzers and liquid chromatography apparatuses, and, in general, flow channels in such apparatuses are required to have excellent chemical resistance and high pressure resistance. As materials that satisfy such requirements, organic materials, such as super engineering plastics including polyether ether ketone resin (hereafter abbreviated as “super enpla”), and inorganic materials, such as silica glass and stainless steel, are known. In particular, a combination of silica glass with polyether ether ketone resin is suitable for a material constituting a flow cell for photometric analysis because of properties of silica glass, such as high light permeability in an extensive wavelength region, excellent chemical resistance, and high stress tolerance, and properties of super enpla, such as excellent moldability and processability, excellent chemical resistance, and high stress tolerance. Accordingly, various bonding techniques have heretofore been attempted. The simplest method for bonding silica glass to resin comprises dissolving resin in a solvent, bringing liquefied resin into close contact with silica glass, and removing the solvent by evaporation. In the case of a material such as super enpla with excellent chemical resistance, however, there has been no sufficient solubilizing solvent, and the method as described above could not be employed.
Accordingly, a method of bonding involving the use of an adhesive agent and a method of bonding via pressure bonding had been employed. When polyether ether ketone resin is bonded to silica glass via the former method, for example, a method of bonding involving the use of an adhesive agent, such as epoxy-based resin or acrylic resin, is recommended. In the case of the latter method, a method making use of a configurational change caused by volume expansion or contraction, such as shrinkage fit or cooling fit, and a method of using a configurational change caused by plastic deformation involving the use of ferrules and nuts have been developed. As another method associated with plastic deformation, a method of bonding comprising heating resin to its melting point or higher, bringing the liquefied resin into close contact with silica glass, and cooling the resultant to resolidify it is known.
As an attempt to allow silica glass to chemically bind to resin, a method of bonding comprising forming membranes containing siloxane groups on both silica glass and resin substrate surfaces via plasma polymerization, and heating the substrates at a low temperature of 100° C. or lower so as to fix the membranes formed via plasma polymerization to each other via polymerization of siloxane groups has been reported (Patent Document 1).